Improved method of turning bridges



' yNrrED *rares ATENT' e -1FF1CE IMPROVED lVIETHOD OF TURNING BRIDGES.

Specification forming part of Letters Patent No. 55,230, dated June 5, 1866.

To all whom it may concern:

Be it known that I, WILLIAM N. BERKELEY, of Cedar Rapids, in the county of Linn and State of Iowa, have invented a new and useful Improvement in Turning Bridges; and I do hereby declare and make known that the following is a full, clear and exact description ofthe same, reference being had to the accompanyin g drawings and the letters and figures marked thereon, which form a part ot' this specification.

My invention relates to that class of bridges for crossing rivers which are so arranged upon a central pier that they may be revolved s0 as to lie parallel with the stream, forming openings upon each side for vessels to pass through when desired; and itconsists in a novel apparatus or arrangement whereby the said bridges are revolved or turned, as aforesaid.

To enable those skilled in the art to ung derstand how to construct and use my said invention, I will proceed to describe its construction and operation with particularity, making' reference in so doing to the aforesaid drawings, in which- Figure l represents a plan or top view of my invention. lFig. 2 is a side elevation of the same; Fig. 3, a vertical central sectional view thereof 5 and Fig. 4 represents a bottom view of the arm F, showing the device for adjusting the tension of the chain, as hereinafter' described.

Similar letters of reference in the different figures denote the same parts of my invention.

A represents the pier, and B the revolving pedestal, of the bridge G, which is supported upon the pier upon a series of balls or conical rollers, as shown, (marked 1),) for the purpose of facilitating the turning of the bridge as required. Around the said pedestal B is arranged a stationary sheave, (marked D,) which is firmly secured in any suitable manner upon the pier, and within which the said pedestal revolves. To one side of the said pedestal is firmly and rigidly secured a horizontal arm, (marked F,) in which the vertical shaft G and the pulley I have their bearings, as shown. Upon the lower end of said shaft G is fixed a suitable drum or friction-roller, H, whose up-- per part is provided with two parallel annular grooves, as shown, and whose lower part rests against the circular bearing E, which is fixed for that purpose uponthe pier,as indicated in the drawings.

The pulley I has a lateral adjustment in its bearings to or from the pedestal, which is effected by the slide J, the diagonal slot c therein moving upon the stationary pin d, as shown. By this means the tension of the chain or cord a, which passes around said stationary sheave D, friction-roller H, and adjustable pulley I, is regulated as desired, and the friction of the same increased.

The apparatus is operated by revolving the shaft G, which is accomplished by any suitable means, as desired.

The chain a is arranged by passing from the sheave D around the roller H in one of the parallel grooves thereupon, thence around the pulley I, from which it passes around H in the other groove before mentioned,and then around the said sheave D. By this arrangementagreat amount of friction, which is the means of operatin g my invention, is obtained.

A less amount of friction could be obtained by dispensing with the adjustable pulley I and passing the chain around the roller H alone, in which case some other means of regulating the tension of the chain or cord would be necessary.

By revolving the shaft G the friction of the chain upon the stationary sheave D and drum H and pulley l, as well as the friction of the roller H upon the circular track E, are all utilized as the power which operates to revolve the bridge, and the power thus obtained is enormous.

In the ordinary mode of revolving bridges the effect of heavy winds upon the bridge when moved from its end supports is very frequently to break the cogs and gearing, when the bridge becomes wholly unmanageable and the sport of the winds. By my arrangement, when the wind strikes upon the bridge under like circumstances, the tension of the chain is thereby increased, thus increasing the resistance of the same to the action of the wind gradually and proportionally to the force of the wind, thus enabling the bridge to be perfectly controlled without the danger and inconvenience of breaking, as the chain may be made of any desired strength.

Having described the construction and operation of my invention, I will now specify what I claim and desire to secure by Letters Patent.

I claiml. In combination with a revolving pedestal, B, the employment of the stationary sheave D and track E, with the friction-rol ler H and chain or its equivalent a, arranged and operating substantially as herein speeied and shown.

2. The combination ofthe revolving pedestal B, sheave D, track E, roller H, pulley I, and

chain a, arranged and operating substantially as shown and described.

3. The employment of the adjustable pulley I, when arranged with the roller H and chain a, as and for the purposes set forth.

` WM. N. BERKELEY. Witnesses:

, L. L. GONE,

JAS. L. BEVER. 

